53(P-23) 酒石酸エーテル誘導体shoyuflavonesの発見と生成機構の解明 : 新規エーテル結合合成酵素の精製と諸性質の探索(ポスター発表の部)

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Nonvolatile components in various brands of fermented soy sauce were analyzed by gradient reversed phase HPLC. The resulting HPLC profiles were correctly classified according to their brands by pattern recognition techniques. Three key components found to significantly contribute to the differentiation were isolated by preparative HPLC and purified by gel-filtration chromatography. FAB-MS, ^1H- and ^<13>C-NMR spectra suggested that these three components having molecular weights of 386, 402 and 418 were isoflavone derivatives. By applying HMBC spectral analysis, these isoflavone derivatives were identified as conjugated ethers of tartaric acid with daidzein, genistein and 8-hydrozygenistein. These new tartaric acid isoflavones were named as shoyuflavones (A, B and C). The study the production mechanism suggested that shoyuflavones were enzymatically produced form isoflavones and (±)-trans-epoxysuccinic acid. Epoxysuccinic acid was produced by Aspergillus fungi but not contained in the original materials. The enzyme responsible for the production of shoyuflavones was purified to homogeneity from the culture extract of A. oryzae. The molecular weight of enzyme was estimated to be 93,000 by SDS-polyacrylamide gel electrophoresis. The activity of enzyme was strictly specific for (±)-trans-epoxysuccinic acid in the presence of genistein. Not only isoflavones but also various flavonoids and their relative compounds were conbined with (±)-trans-epoxysuccinic acid by the enzyme. Using the purified enzyme, seven products (I-VII) were obtained from five flavonoids. On the basis of NMR and MS spectra, these products were identified as tartaric acid derivatives that had been produced by connect one or two tartaric acid molecules with ether linkage. Shoyuflavones showed intense inhibition against activities of histidine decarboxylase. This novel enzyme can synthesize various unique derivatives of flavonoids and related compounds. In the near future, useful biological activities may be found among a series of such new compounds.
天然有機化合物討論会の論文
2000-10-01

53(P-23) 酒石酸エーテル誘導体shoyuflavonesの発見と生成機構の解明 : 新規エーテル結合合成酵素の精製と諸性質の探索(ポスター発表の部)

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